android/src/com/android/tools/idea/sdk/remote/internal/packages/LayoutlibVersionMixin.java

/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.tools.idea.sdk.remote.internal.packages;

import com.android.annotations.NonNull;
import com.android.annotations.Nullable;
import com.android.sdklib.repository.PkgProps;
import com.android.tools.idea.sdk.remote.internal.sources.RepoConstants;
import com.android.utils.Pair;
import org.w3c.dom.Node;

import java.util.Properties;

/**
 * Helper class to handle the layoutlib version provided by a package.
 */
public class LayoutlibVersionMixin {
  public static final int LAYOUTLIB_API_NOT_SPECIFIED = 0;
  public static final int LAYOUTLIB_REV_NOT_SPECIFIED = 0;

  /**
   * The layoutlib version.
   * The first integer is the API of layoublib, which should be > 0.
   * It will be equal to {@link #LAYOUTLIB_API_NOT_SPECIFIED} (0) if the layoutlib
   * version isn't specified.
   * The second integer is the revision for that given API. It is >= 0
   * and works as a minor revision number, incremented for the same API level.
   */
  private final Pair<Integer, Integer> mLayoutlibVersion;

  /**
   * Parses an XML node to process the {@code <layoutlib>} element.
   * <p/>
   * The layoutlib element is new in the XSD rev 4, so we need to cope with it missing
   * in earlier XMLs.
   */
  public LayoutlibVersionMixin(Node pkgNode) {

    int api = LAYOUTLIB_API_NOT_SPECIFIED;
    int rev = LAYOUTLIB_REV_NOT_SPECIFIED;

    Node layoutlibNode = RemotePackageParserUtils.findChildElement(pkgNode, RepoConstants.NODE_LAYOUT_LIB);

    if (layoutlibNode != null) {
      api = RemotePackageParserUtils.getXmlInt(layoutlibNode, RepoConstants.NODE_API, 0);
      rev = RemotePackageParserUtils.getXmlInt(layoutlibNode, RepoConstants.NODE_REVISION, 0);
    }

    mLayoutlibVersion = Pair.of(api, rev);
  }

  /**
   * Stores the layoutlib version in the given {@link Properties}.
   */
  void saveProperties(Properties props) {
    if (mLayoutlibVersion.getFirst().intValue() != LAYOUTLIB_API_NOT_SPECIFIED) {
      props.setProperty(PkgProps.LAYOUTLIB_API, mLayoutlibVersion.getFirst().toString());
      props.setProperty(PkgProps.LAYOUTLIB_REV, mLayoutlibVersion.getSecond().toString());
    }
  }

  @Override
  public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + mLayoutlibVersion.hashCode();
    return result;
  }

  @Override
  public boolean equals(Object obj) {
    if (this == obj) {
      return true;
    }
    if (obj == null) {
      return false;
    }
    if (!(obj instanceof LayoutlibVersionMixin)) {
      return false;
    }
    LayoutlibVersionMixin other = (LayoutlibVersionMixin)obj;
    if (!mLayoutlibVersion.equals(other.mLayoutlibVersion)) {
      return false;
    }
    return true;
  }
}